The 700 pages of concluding arguments filed with the Tax Court of Canada (TCC) in Cameco Corporation’s $2.1 billion transfer pricing dispute with the Canada Revenue Agency (CRA) marks a new era of complexity for corporate tax litigation in Canada.

“That type of filing is unheard of and may signal the evolution of a kind of trench warfare in the Tax Court,” said a veteran tax litigator who spoke on condition of anonymity because of the lawyer’s connection to the ongoing case.

After 65 days of trial, the parties made their closing arguments in September 2017. Justice John Owen reserved his decision, which, by some accounts, may not be issued until 2019 owing to its legal and factual intricacies and the implications for business.

The heart of the dispute with the CRA is the company’s practice of selling uranium to a subsidiary in Switzerland, which it then sells on the market, incurring fewer taxes. The company settled a similar claim with the U.S. Internal Revenue Service last year.

Jacques Bernier, a tax litigator in Baker McKenzie’s Montreal office, believes that both the personal and professional attitudes of lawyers on both sides of tax cases have changed over the last 15 years.